Stereophonic pick-up



June 9, 1964 M. DE VRIES 3,136,555

STEREOPHONIC PICK-UP Filed June 27, 1960 2 Sheets-Sheet 1 Fry". .2

fir/m/ ac Wes INVENTOR.

BY Cm *Qwl m June 9, 1964 M. DE VRIES 3,136,555

STEREOPHONIC PICK-UP Filed June 27, 1960 2 Sheets-Sheet 2 BY mp/wz wmUnited States Patent O f 3,136,555 STEREOPHONIC PICK-UP Machiel deVries, Amsterdam, Netherlands, assignor to Ronette Piezo ElectrischeIndustrie, N.V., Amsterdam, Netherlands, a corporation of theNetherlands Filed June 27, 1960, Ser. No. 38,775

Claims priority, application Netherlands July 2, 1959 13 Claims. (Cl.274-37) The present invention relates to a stereophonic pick-upcomprising a casing in which two transducers are secured, eithertransducer being connected with a common stylus holder by a couplingmeans, said stylus holder having a stylus fitted to its one end andhaving its other end accommodated within the smaller of the two anglesformed by the interconnected ends of said coupling means.

If a pick-up of this type is to have a satisfactory separating capacitythe coupling means should have a relatively thin elongated shape. If thecoupling means have this shape they will have an adequate yieldingnessin transverse direction, it is true, but the consequence thereof at thesame time is that in longitudinal direction said coupling means can takeup but a very slight force without collapsing. This means that thecoupling means are no longer in a position then to take up the reactionforce of the stylus pressure, so that in this respect special provisionsare to be taken.

The object of the invention is to so construct the stylus holder thatwhen the pick-up is placed ona record a mechanical stress will manifestitself in the coupling means which levels out the said reaction force.If desired, the construction may be so that already after the assemblyof the pick-up there is a certain pre-stress in the coupling means whichwhen the pick-up is placed on a record increases to a value capable ofwithstanding the reaction force.

A further object according to the invention is that during the mountingof the stylus holder in the casing, said stylus holder will lie in thecorrect position in respect of the coupling means without it beingnecessary to pay any special attention thereto.

To achieve these objects according to the invention the pick-up of thetype referred to is so constructed that during its mounting the stylusholder which is secured in a support, only admits of being brought inits place along a fixed track, which track as regards its shape andlocation relative to the casing is defined by guide means with whichsuch support and said casing respectively are provided, said track beingso shaped and located that at least when the support covers the lastportion of said track the produced part of said other end of the stylusholder is located within the angle enclosed by the coupling means, thearrangement being such that said other end of the stylus holder ispositively brought in itsseat on the ends of the coupling means.

In addition the pick-up according to the invention may have for itsfeature that the support has a predetermined seat relative to thecasing, which seat can only be reached by moving the support along afixed track in the direction towards the coupling means, said track as3,136,555 Patented June 9, 1964 tion adapted to cooperate with saidresilient member regards its shape and location being defined bycoopwhile during said cooperation the stylus holderwhich is tiltablysupported by the support is so moved relative to said support by saidresilient member that said stylus holder. moves through a positiveresultant path.

The invention will be elucidated hereinafter with reference to' theaccompanying drawings showing some embodiments.

In said drawings: p FIGURE 1 is a partial bottom view of a firstembodiment of the pick-up provided with one stylus holder;

\ FIGURE 2 is likewise a partial showing of the pickup according toFIGURE 1, said showing being partly an elevation and partly a sectionalview;

FIGURE 3 is a cross-sectional view on the line III-III in FIGURE 2;

FIGURE 4 shows the detachable support of the stylus holder inperspective;

FIGURE 5 shows a slot'provided in the pick-up according to FIGURES 1 and2, in which slot .the support according to FIGURE 4 fits;

FIGURE 6 is a sectional View of the type as shown in FIGURE 3, but of asecond embodiment which is provided with two stylus holders locateddiametrically opposite each other;

FIGURE 7- is a longitudinal sectional view of a support different fromthe support shown in the preceding figures; FIGURES is a cross-sectionalview on the line VIII- VIII in FIGURE 7;

FIGURE 9 is a plan view of a support removed from the casing. Within acasing 1 two crystal elements 2 and 3 are located the one ends of whichare clamped inthe casing 1 in a manner not shown. On each of the otherfree ends of the crystal elements 2 and 3 a sleeve 5 and 6 respectivelyis fitted, for which purposesaid sleeves, are each providedwith ,alongitudinal slot 7 and 8 respectively. From the ends 9 and 10 of thesleeves 5 and 6 arms 11 and 12 respectively depend which areinterconnected at 13. .The arms 11 and 12 are in the form of thinelongated strips and they are integral with each other as well'as withthe associated sleeves 5 and 6 respectively. The assembly of the sleeves5 and 6 and the arms 11 and 12 is made from a relatively soft syntheticmaterial. The crystal elements 2 and 3 have their main faces arranged atright angles to eachother, as appears fromFIGURE 3. Also the armsdl and12 are at least substantially at right angles to each other.

Within the angle formed at 13 by the arms 11 and 12 a stylus holder 14is located which has its end provided with a stylus 15. The stylusholder 14 is secured in a block 16, made from a resilient kind ofsynthetic material and for thispurpose the block contains an opening 17.Said block 16 issec uredto-a substantially gutter-shaped support 18which has been separately shown in FIGURE 4. Said support 18 has asubstantially trapezium-shaped crosssection and may be slid into and outof a slot in the casing 1, which slot is separately shown in FIGURE 5and which is generally-designated by the reference numeral 19. Theuppermost portion of the slot 19 is formed complementary in respect ofthe support 18. The slot 19, however, is slightly deeper than the heightof the support 18, because in addition to two oblique walls 20 and 21the slot also has two straight walls 22 and 23.

In FIGURE 3 the support 18 is shown in its place and it will be seenthat a free space 24 is left above the support,

which free space is on either side defined by the walls 22 I 3 and 23.On the bottom of the slot 19 a leaf spring 26 is secured which in theinoperative position is bent to extend away from said bottom. From thewalls 20 and 21 two projections 27 and 28 project, while in the support18 complementary shaped recesses 29 and 30 are provided. If the support18 is to be slid into, the slot 19, for which purpose according toFIGURES l and 2 the support is to be moved from the left to the right,the lower faces 31 and 32 of the support 18 are to be moved over theprojections 27 and 28. The spring 26 is then slightly pressed towardsthe bottom 25. This means that the stylus holder 14 is moved upwardlytogether with the support 18, the

end 33 of the stylus holder automatically arriving within the angleenclosed by the arms 11 and 12, i.e., above the junction 13. When therecesses 29 and 30 are located above the projections 27 and 28 thespring 26 will be partly released, so that the'support 18 is urged awayfrom the bottom 25 of the slot and it will then occupy the position moreparticularly shown in FIGURES 2 and 3. The end 33 of the stylus holder14 then bears against the junction 13, a certain pre-stress beingimparted to the arms 11 and 12. When the pick-up, in the position shownin FIGURE 2, is placed on a gramaphone record the stylus holder 14 willslightly tilt about the block 16, i.e., to a more horizontal position.The reaction force acting on needle 15 is then taken up by the arms 11and 12.

FIGURE 6 shows a second embodiment comprising a second stylus 34, thepoint of which has another radius diameter than the point of the stylus15, which is of importance for enabling the pick-up to track grooves ofdifferent width. The sleeves Sand 6 are laterally provided withextensions 35 and 36 to which arms 37 and 38 are secured, which at 39merge in to each other. Within the substantially right angle at 39between the arms 37 and 38 a stylus holder 40 is locatedwhich carriesthe stylus 34. The other structural details are identical to thecorresponding details described hereinbefore and need not be mentionedseparately therefore.

In FIGURES 7, 8 and 9 a support of a different construction is shown.Said support 41 has a trapeziumshaped cross-section as may be seen fromFIGURE 8 and is located in a recess 42 of the casing 43. In thisembodiment the support 41 fits the recess 42 without play, so that thesupport 41 can only be moved according to a straight path in respect ofthe casing 43 when it is inserted or removed from the casing. Thesupport again supports a stylus holder 44 with a stylus 45, the stylusholder passing through a strip of elastic material 46 acting as abearing, which strip of elastic material is secured in the support 41.Two slit-shaped passages 47 and 48 are provided in the support 41. Asubstantially U-shaped leafspring 49 passes through said passages. Theone end of the spring "49 extending through the passage 48 ends in twostrips 50 and 51 which extend downwardly on either side of the stylusholder 44 and which engage the resilient strip 46 by means of theirhook-shaped ends 52 and 53 respectively. In this manner, therefore, theleaf spring 49 has one end anchored in the support 41.. The centralportion of the spring 49 is slightly bent upwards at 54, while its end55 extends through the slit 47. Said end 55 is recessed at 56 and islocated very closely to the stylus holder 44. The bent portion 54 of thespring 49 is adapted to cooperate with a projection 57 which forms partof the easing 43 and is secured to the upperwall of the recess 42.

When the support 41 is inserted into the recess 42 in a direction fromthe left to the right in FIGURE 7, said a support after having coveredpart of its track will start pressing the projection 57 against thecentral portion of the leaf spring 49. Seeing that the one end of thespring 49 is secured from movement the other free end 55 will be presseddownwardly. The tip' of the free. end. will then start pressing againstthe stylus holder 44, the recess 56 having a useful stylus holderlocating action.

If the portion of the stylus holder 44 which is located at the left inFIGURE 7 has moved downwardly until it has arrived at the position shownin dotted lines, the right hand portion of the stylus holder will havemoved upwardly. The spring 49 and the projection 57 are so arranged thatthe right hand portion of the stylus holder has been lifted upwardly atthe very moment when said portion of the stylus holder has reached thecorner 13 between the arms 11 and 12.

When the support 41 has reached the position in which it is entirelyinserted in the casing the projection 57 has passed the bent portion 54of the leaf spring 49, so that the free end 55 of the leaf spring 49 hasagain moved upwardly and consequently the stylus holder 44 has beenreleased at the very moment when its right hand end has reached thecorrect position. I

'When the support is taken out of the casing the reverse naturally takesplace, so that the stylus holder 44 will again make a tilting movementat the same moment when the right hand end of the stylus holder willstart disengaging the arms 11 and 12. There is no chance therefore oftoo large a pressure being exerted on the arms 11 and 12 when. thesupport is detached from the casing.

In the embodiments described hereinbefore the coupling means alreadyhave a certain pre-stress after the mounting of the stylus.holder,.which pro-stress is in point of fact generatedby a certaindeformation of the elastic block in which the stylus holder issupported.

According to an alternative embodiment the stylus holder is free fromthe coupling means as long as the pick-up does not bear on a record. Inthis case therefore a stress in the coupling means will only come tobeing when the pick-up is in its operative position.

I claim:

1. In a binaural cartridge means for use with V-groove sound recordshaving separate undulations on the opposed faces of the groove casingmeans, support means, a pair of transducer means each having a mountingportion and a driven portion, means to attach the mounting portions ofthe transducer means to said casing means to position the drivenportions in spaced side-by-side relationship, coupling means including apair of downwardly convergent arms arranged generally normal to theplanes of the respective faces of a V-groove and flexurally joined attheir lower ends, means to mount the coupling means to operativelyengage the upper portions of the arms with the driven portions of therespective transducer means, stylus means including an elongated shankhaving a stylus-tip at one end, means to pivotally mount said shank onsaid support means, said support means being removably attached to saidcasing means, said support means being engaged with the'shank mediallyof the ends thereof to position the other end of the shank in operativeengagement with said juncture of coupling arms when the support means isattached to the casing means to exert a downwardly directed initialstress on said arms under no-load conditions.

2. The invention as defined in claim 1, wherein the lower ends of thecoupling arms define an acute angle at said flexural juncture, and saidother end of the shank is received within the space defined by saidacute angle to bear downwardly against said arms at said juncture.

3. The invention as defined in claim 2, wherein said pivotal mountingmeans for the stylus shank includes a resilient element connectedbetween the shank and the support means.

4. The invention as defined in claim 1, wherein said casing means isprovided witha slideway extending in a direction normal to the plane ofthe coupling means, and said support means for thestylus shank includesslide means receivable in said slideway.

5. Theinvention as defined in claim 4, wherein said support meansincludes a resilient element and said stylus shank is pivotallyconnected to the support means by said resilient element, said shankbeing normally mounted in an inclined position with the stylus tip atthe lower end and the other end of the shank being positioned forengagement with the coupling means when the support means is movedrearwardly.

6. The invention as defined in claim 5, wherein said other end of thestylus shank will exert an initial downward force against the couplingmeans when moved into engagement therewith.

7. The invention as defined in claim 4, wherein said slideway includes alongitudinally extending recess provided in said casing means, saidrecess having opposed inclined walls, said support means being providedwith inclined side walls for dovetailed sliding engagement with walls ofthe recess, the height of the support means being less than that of therecess, and biasing means positioned in said recess for engagement withthe top of the support means to urge the side walls of the support meansinto engagement with the side walls of the recess.

8. The invention as defined in claim 7, wherein one of said side wallsis provided with projecting detent means, the respective complementaryside wall being provided with a recess to receive said detent means,said detent being positioned to limit rearward movement of the supportmeans, said support means being upwardly tiltable against said biasingmeans to clear said detent and permit further rearward movement of thesupport means, and downwardly tiitable after said further rearwardmovement into operative position when the detent is in alignment withits cooperating recess.

9. The invention as defined in claim 8, wherein the pivotal mountingincludes a resilient elementto connect said shank with the support meanswhereby said other end of the stylus shank will exert an initialdownward force against the coupling when downwardly tilted intoengagement therewith.

10. In a binaural sound reproducing cartridge means for use selectivelywith sound records having grooves of differing physical characteristics,said grooves being of the character wherein two distinct undulatorysurfaces are impressed therein, including, support means, a pair oftransducer means having a mounting portion and a driven portion, meansto attach said mounting portions to the support means, first and secondstylus means, each said stylus means being physically compatible with aparticular character of record groove, means to attach said stylus meansto the support means for selective engagement with a record groove, andcoupling means to transmit vibrations from either one of said stylusmeans to both said transducer means, said coupling means including firstand second vibration transmitting mechanisms, each said mechanismincluding a driven portion and two driving portions and includingenergy-discriminating elements whereby vibrations from the respectiveundulatory surfaces of a groove are transmitted separately to therespective driving portions of the mechanism, the force transmittingcharacteristics of one said mechanism diifering from the forcetransmitting characteristics of the other mechanism, and means to mountsaid coupling means to position the driven portions of the vibrationtransmitting mechanisms in operative engagement respectively with saidfirst and second stylus means and to position one of the drivingportions of each vibration transmitting mechanism in operativeengagement with the driven portion of one of the transducer means andthe other of the driving portions of each vibration transmittingmechanism in operative engagement with the driven portion of the othertransducer means.

11. The invention as defined in claim 10, wherein said transducer meanscomprises two elongated flat strips of piezoelectric material, saidstrips being mounted in spaced parallel relationship, said couplingmeans is integrally formed of elastomeric material, and said means toconnect the coupling means to the transducers comprises a. pair ofsleeve means formed integrally with the coupling means of elastomericmaterial to embrace the respective one ends of the piezoelectric strips.

12. The invention as defined in claim 11, wherein saidpiezoelectricstrips are disposed in angularly related planes, saidcoupling means including two pairs of L-shaped levers, one leg of eachof the L-shaped levers in one pair of said levers being formed by a pairof integrally formed projections each extending respectively from arespective sleeve means in the plane of a respective piezoelectricstrip, the corresponding leg of each of the L-shaped levers in thesecond pair of levers being formed by a pair of integrally formedprojections each extending respectively from a respective sleeve meansin a plane normal to the plane of a respective piezoelectric strip.

13. The invention as defined in claim 12, wherein the length of thefirst-mentioned projections is greater than the length of thelast-mentioned projections.

References Cited in the file of this patent UNITED STATES PATENTS2,934,610 Dieter Apr. 26, 1960

1. IN A BINAURAL CARTRIDGE MEANS FOR USE WITH V-GROOVE SOUND RECORDSHAVING SEPARATE UNDULATIONS ON THE OPPOSED FACES OF THE GROVE CASINGMEANS, SUPPORT MEANS, A PAIR OF TRANSDUCER MEANS EACH HAVING A MOUNTINGPORTION AND A DRIVEN PORTION, MEANS TO ATTACH THE MOUNTING PORTIONS OFTHE TRANSDUCER MEANS TO SAID CASING MEANS TO POSITION THE DRIVENPORTIONS IN SPACED SIDE-BY-SIDE RELATIONSHIP, COUPLING MEANS INCLUDING APAIR OF DOWNWARDLY CONVERGENT ARMS ARRANGED GENERALY NORMAL TO THEPLANES OF THE RESPECTIVE FACES OF A V-GROOVE AND FLEXURALLY JOINED ATTHEIR LOWER ENDS, MEANS TO MOUNT THE COUPLING MEANS TO OPERATIVELYENGAGE THE UPPER PORTIONS OF THE ARMS WITH WITH THE DRIVEN PORTIONS OFTHE RESPECTIVE TRANSDUCER MEANS, STYLUS MEANS INCLUDING AN ELONGATEDSHANK HAVING A STYLUS TIP AT ONE END, MEANS TO PIVOTALLY MOUNT SAIDSHANK ON SAID SUPPORT MEANS, SAID SUPPORT MEANS BEING REMOVABLY ATTACHEDTO SAID CASING MEANS, SAID SUPPORT MEANS BEING ENGAGED WITH THE SHANKMEDIALLY OF THE ENDS THEREOF TO POSITION THE OTHER END OF THE SHANK INOPERATIVE ENGAGEMENT WITH SAID JUNCTURE OF COUPLING ARMS WHEN THESUPPORT MEANS IS ATTACHED TO THE CASING MEANS TO EXERT A DOWNWARDLYDIRECTED INITIAL STRESS ON SAID ARMS UNDER NO-LOAD CONDITIONS.